During the first trimester your body undergoes many changes. Hormonal changes affect almost every organ system in your body. These changes can trigger symptoms even in the very first weeks of pregnancy. Your period stopping can be a sign that you are pregnant.

Other changes may include:

• Extreme tiredness
• Tender, swollen breasts. Your nipples might also be more prominent..
• Upset stomach with or without vomiting (morning sickness)
• Cravings or distaste for certain foods
• Mood swings 
• Sensitivity to odors
• Constipation (trouble having bowel movements)
• Need to pass urine more often
• Headache
• Heartburn
• Weight gain or loss

As your body changes, you might need to make changes to your daily routine, such as going to bed earlier or eating frequent, small meals.  Fortunately, most of these discomforts will most likely go away as your pregnancy progresses, and there are those who will have no discomfort at all.  If you have been pregnant before, you might feel differently this time around.  Each pregnancy can be different depending on the individual woman.